Grain dryer module

ABSTRACT

A module used with a granular material dryer, such as a grain dryer. The module includes an outer wall, at least one channel and at least one outlet aperture. The channel is positioned relative to the wall such that the channel is in fluid communication with heated air otherwise passing through the dryer. The outlet aperture is in communication with a suction mechanism. Finally, the channel is associated with the outlet aperture such that the heated air will enter the outlet aperture, via activation of the suction mechanism, whereas the granular material will not occlude the channel of the outer aperture. In one preferred embodiment, the module of the present invention is configured to be insertable with an existing dryer to improve drying efficiency.

CROSS REFERENCE TO COPENDING APPLICATION

This application claims the benefit of U.S. Provisional application Ser.No. 60/021,587, filed Jul. 11, 1996.

TECHNICAL FIELD

The present invention relates broadly to the field of apparatus used forextracting moisture from granular materials. More narrowly, however, itdeals with dryers which function to extract moisture from grain as aconsequence of vaporization to the moisture resulting from heat transferas the grain passes downwardly through a plenum or a series of plenummodules. A specific focus of the invention is a module which isinsertable in an existing dryer to more efficiently effect the dryingprocess.

BACKGROUND OF THE INVENTION

Various apparatus have been used for drying granular materials. Suchapparatus are particularly useful in treating grains such as oats,rapeseed and soybeans. Moisture is removed to process a valuablefoodstuff and to maximize the period of time over which the grain can bestored.

Proper processing is facilitated in other ways also. The objectivespreviously discussed can also be obtained, in some measure, by thermaltreatment of the grain.

Depending upon the particular grain, a number of effects can beachieved. Moisture removal and heat treatment can have the effect ofdeactivating fat-reducing enzymes. This results in lengthening thestorability of the grain. In some cases, the treatment results in theremoval of bitter tastes and brings out, more effectively, pleasingflavor and aroma.

Grains, when properly treated, are heated generally evenly over adesired period of time. The time over which heating occurs is dependentupon capacity of the treating apparatus and other factors. Heating canbe maintained, if desired, for several hours by regulating the rate offlow of the grain through a treating apparatus. Product temperatures canbe elevated up to approximately 130° C.

One apparatus used for drying, for example, oats has been developed byBuhler-Miag. The apparatus design employs a plurality of modules stackedvertically to define a vertically-elongated processing plenum. The grainis introduced in the uppermost module, and it passes downwardly, througha plenum formed by the stacked modules, to an egress aperture controlledby appropriate apparatus. Introduction of grain into the apparatus,proximate the top end thereof, is coordinated with discharge of thegrain from the bottom so that the device is maintained in asubstantially full disposition at all times.

The grain moves through the various modules as it passes downwardlythrough the column of interconnected modules. The time to which thegrain is exposed to thermic treatment is governed by a number offactors, including the volume of grain in the apparatus and the flowrate of the product downwardly.

Each module employs a plurality of rows of staggered closed ductsextending across the modules. Staggering of the ducts in adjacent rowsfacilitates an even heating of the grain. The ducts are closed incross-section, and the ducts convey steam from an inlet manifold on oneside of the module to an outlet manifold on the other side of themodule. One type of duct employed in the Buhler-Miag dryer is generallyhexagonal in cross-section and of a generally vertically elongatedconfiguration.

The Buhler-Miag dryer varies from other prior art devices with regard tothe extent of moisture removed from the grain. Typical, however, ofdevices of this type known in the prior art is a removal of 0.1-0.2% ofthe moisture as the temperature of the grain is elevated from between50° F.-150° F.

It is to these dictates of the prior art and the shortcomings thereof asdiscussed above that the present invention is directed. It is animproved structure, usable in combination with, for example, aBuhler-Miag dryer to increase the efficiency thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective illustration of a drying column employingmodules, as known in the prior art, and a module in accordance with thepresent invention;

FIG. 2 is a side elevational view of the drying column of FIG. 1, someportions thereof being broken away;

FIG. 3 is a top plan view of the drying column of FIG. 1, some portionsthereof being broken away;

FIG. 4 is an enlarged view of structure circled at “4” in FIG. 2illustrating means for maintaining adjacent modules securely connectedone to another, as known in the prior art;

FIG. 5 is a cross-sectional view of a steam duct, as known in the priorart; and

FIG. 6 is a cross-sectional view illustrating a steam-conducting conduitemployed in the module in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein like reference numerals denotelike elements through the several views, FIGS. 1, 2, and 3 illustrate agrain drying column 10 employing the present invention. The column 10employs a plurality of modules 12, as known in the prior art, whichdefine a plenum 14 through which grain 16 passes vertically downwardlythrough the column 10. Also included (shown third from the bottom inFIG. 2) is a special module 18 in accordance with the present inventionas will be discussed hereinafter. The modules 12, 18 can vary in theirvertical dimension, but a typical vertical dimension for a module is onthe order of approximately three feet. Since the column 10 illustratedin FIGS. 1 and 2 includes eight total modules, its vertical height wouldbe on the order of twenty-four feet plus the vertical dimension of eachof an ingress truncated pyramid section 20 at the top of the column 10,a rotary valve section 22 below the treating modules, and an invertedegress, truncated pyramid section 24 at the bottom of the column 10. Itis not uncommon for the total vertical dimension of the column 10 to beon the order of approximately thirty feet.

As previously discussed, the column 10 includes a generally truncatedpyramidal section 20 at the top of the column 10 which functions toreceive grain from a feed source (not shown). The grain 16 is depositedthrough an aperture 26 at the top of the pyramidal section 20 and,eventually, fills the plenum 14 defined by the mated modules. The bottomof the plenum 14 is defined by a floor comprising one or more rotaryvalves 28 which can be operated to afford egress to the grain 16 afterit has been processed in the plenum 14. FIG. 2 illustrates sevenseparate rotary valves 28 at the bottom of the plenum 14.

After grain 16 has been passed through the rotary valves 28 in aselective fashion, it is deposited into the inverted egress pyramidalsection 24. It can, thereafter, be transferred by appropriate conveyingstructure (not shown) to a storage site.

A sensor (not shown) can be provided in the ingress pyramidal section 20in order to measure the location of the upper surface of grain 16 withinthe processing apparatus. The sensor can, in turn, be coordinated withthe rotary valves 28 in order to maintain the grain 16 at a desiredlevel. That is, if the level drops too low, the rotary valve operationwill be slowed down so that the level of the grain 16 at the top of thecolumn 10 can be elevated. Conversely, if the level of grain 16 becomestoo high, rotary valve operation can be maintained more constant untilthe level of grain drops.

The drying and heating modules 12 known in the prior art include aplurality of rows of ducts 30, as best illustrated in FIG. 2. As seen inFIG. 5, each of these ducts 30 can be a closed hexagonal cross-sectionedtube through which steam can be conducted. The steam is heated to atemperature so that, as it is passed through each duct 30, from an inletmanifold 29, through the duct 30, into an outlet manifold 31, andthrough exit tubes 33, it will elevate the temperature of the grain 16to a level at which drying and thermic treatment will be facilitated.

The prior art treating modules 12 illustrated in FIG. 2 show arrangementof the ducts 30 wherein ducts 30 in one row are staggered from ducts 30in an adjacent row. This staggering enables facilitation of heating ofthe grain 16, since virtually all of the grain 16 will engage multipleducts 30. Further, each duct typically has a width of approximately oneinch and a vertical height of approximately three inches. Suchdimensioning is coordinated with the spacing between adjacent ducts 30in one row and the location of ducts in an adjacent row to furtherfacilitate maximization of heat transfer.

FIG. 4 illustrates a manner of mating adjacent modules. Each module isdefined by a vertical encircling wall, and upper and lower ends of thiswall are provided with flanges 32 which, when the modules are properlypositioned relative to one another, abut with cooperating flanges ofadjacent modules. A seal 34 is inserted between the flanges 32 prior tothe time that they are brought into engagement, and the flanges 32 andinterposed seal 34 are provided with registered apertures for receivingthe shank of a bolt 36. A nut 38 is secured to a distal end of the bolt36, after it has been passed through corresponding registered apertures,to hold one module in tight engagement with another.

FIG. 6 best illustrates the construction of channels 40 disposed withinthe special processing module 18 (that is, the third from the bottommodule viewed in FIG. 2). These channels 40 have a construction andorientation similar to the ducts 30 of the prior art modules 12 (thatis, as seen in the figures, generally transverse to a direction ofpassage of particulate material through plenum 14), but the bottom ofeach such channel 40 is open. As heated air is introduced into theplenum 14 proximate upper and lower ends thereof, it will, as it passesdownwardly through the plenum from the upper end and upwardly throughthe plenum from the lower end seep into channels 40 as it passes throughthe treating column, and, specifically, through the special module 18.As the heated air passes through the grain 16 in vertically traversingthe treating column, it will absorb moisture from, and dry, the grain16.

A suction mechanism 62 downflow of the drying apparatus, facilitatespassage of the treating heated air through an outlet aperture 42 in awall 44 of the special processing module 18 and into an outlet manifold68. Thereafter, the heated air will be processed in a manner as will bediscussed hereinafter.

Passage of the heated air into, and through, channels 40 will befacilitated because of the suction mechanism downflow of the dryingapparatus. Such passage of the heated air will not be occluded throughchannels 40 in view of the fact that the grain 16 passing through theplenum 14 is passing downwardly. The expected profile of grain flowaround channels 40 is best seen in FIG. 6. The heated air passingthrough the grain 16 into the channels 40 and through apertures 42 intooutlet manifold 68 will effectively accomplish drying.

FIG. 1 illustrates a heated air conduction system for use in combinationwith the treating column. Illustrated is a hot air plenum 48 which isdown-flow from a blower 50 having a fan 52 mechanism. Heated air fedinto the plenum 14 by the blower 50 is, thereafter, passed through areducer manifold 54 and into upper and lower feed legs 56, 58 whichconduct the heated air to manifolds 57, 60 proximate the top and bottom,respectively, of the column 10. Heated air is fed directly into theplenum 14 by the upper feed leg 56 for passage into manifold 57 andintroduction into grain 16 through channels 59 extending across ingresssection 20, and, thereafter, downwardly through the grain 16 in thedirection of movement of the grain 16 through the plenum 14. Additionalinlet manifolds 57 connected at various points along the column 10 maybe included. The lower feed leg 58 feeds a manifold 60 for injection ofthe heated air proximate the lower end of the column 10 and passage in acounter-current direction to the flow of the grain. Heated air thuspassing through the plenum 14 is sucked out of the plenum 14 through thespecial module 18, via channels 40, and into a cyclone 62 whereparticulate material is removed through a controlled rotary valve 64.

The figures also illustrate inlet and outlet manifolds for each of theprior art modules. These, of course, as discussed hereinbefore, areoperated in the same manner as they are in the prior art. That is,heated steam is fed to the inlet manifolds 29 from where it passesthrough the ducts 30 to the respective outlet manifolds 31. Thereafter,it is reprocessed for subsequent use.

By employment of the special module 18 as described herein, it has beenfound that efficiency of the dryer can be improved significantly. Where,as previously discussed, prior art dryers remove 0.1-0.2% of themoisture in the column, it is estimated that drying in the range of 1%to 3% should be able to be achieved for many grain or oilseed productswhen an apparatus modified by employment of the special module describedherein is utilized.

It will be understood that this disclosure, in many respects, is onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, material, and arrangement of parts without exceeding thescope of the invention.

What is claimed is:
 1. Apparatus for drying particulate material, comprising: (a) a wall defining a plenum through which the particulate material passes downwardly and heated gas passed upwardly; (b) at least one channel, immersed beneath an upper surface of particulate material in said plenum, extending through said plenum generally transversely to a direction of passage of particulate material and heated gas, said at least one channel being in fluid communication with said plenum and having an egress orifice, in alignment therewith, through said wall; and (c) a suction mechanism for taking a vacuum through said orifice.
 2. Apparatus for drying particulate material, comprising: (a) a wall defining a plenum, having an upper end and a lower end, through which particulate material passes downwardly from said upper end to said lower end and heated gas passed upwardly; (b) at least one channel, immersed beneath an upper surface of particulate material in said plenum and extending through said plenum generally transversely to directions of passage of particulate material downwardly and heated gas upwardly therethrough, said at least one channel being in fluid communication with said plenum and having an egress orifice, in alignment with said channel, through said wall; (c) an upper manifold in communication with said plenum proximate said upper end thereof; (d) a lower manifold in communication with said plenum proximate a lower end thereof; (e) means for introducing a heated gas into said upper and lower manifolds; and (f) a suction mechanism for taking a vacuum through said orifice.
 3. Apparatus in accordance with claim 2 wherein said means for introducing a heated gas into said upper and lower manifolds comprises a blower driving gas, heated in an external manifold, into feed legs communicating with said upper and lower manifolds.
 4. Apparatus in accordance with claim 2 wherein said wall comprises a plurality of vertically stacked modules together defining said plenum.
 5. Apparatus in accordance with claim 4 wherein each of said modules has a vertical dimension of approximately three feet.
 6. Apparatus in accordance with claim 5 wherein said plenum has a vertical height of at least 20 feet. 